It takes 6 hours to fill 2 tanks of the same size with a pump. How long will it take to fill 5 such tanks with the same pump? Class 8

It takes 6 hours to fill 2 tanks of the same size with a pump. How long will it take to fill 5 such tanks with the same pump? Class 8

Question 1.

It takes 6 hours to fill 2 tanks of the same size with a pump. How long will it take to fill 5 such tanks with the same pump? Class 8

Solution:

Between hours and number of tanks, there is a direct propotion.

Let the time required be x hours.

2 : 5 : : 5 : x

or 2 × x = 5 × 6

Hence, x = [latex]\frac{6 \times 5}{2}[/latex] = 15 hours.

Question 2.

A given set of chairs are arranged in 25 rows, with 12 chairs in each row. If the chairs are rearranged with 20 chairs in each row, how many rows does this new arrangement have? Class 8

Solution:

Let there hex rows in this arrangement.

So, 20 × x = 12 × 25

or x = [latex]\frac{12 \times 25}{20}[/latex] = 15.

Question 3.

A school has 8 periods a day, each of 45 minutes duration. How long is each period, if the school has 9 periods a day, assuming that the number of school hours per day stays the same? Class 8

Solution:

Let each period be of x minutes in the new arrangement.

So, 8 × 45 = 9 × x

or x = [latex]\frac{8 \times 45}{9}[/latex] = 40 minutes.